1. Field of the Invention
The present invention relates to a shaping tool for a workpiece, in particular for plastic shaping of a tube end, with a clamping device, including a plurality of clamping segments, for the workpiece and with a compression head, which in particular includes on one side a recess for forming a to-be-shaped contour of the workpiece and on the opposing side an attachment means for connecting to a shaping piston of a device for deforming the workpiece.
Furthermore, the present invention relates to a device for deforming a workpiece with a shaping subassembly actuatable by the pressure of a fluid and with a clamping subassembly disposed on a common longitudinal axis, actuatable by the pressure of the fluid.
2. Description of Related Art
A shaping tool and a device of the type mentioned are known from EP 1 494 827 B1. This document describes a device for shaping of workpieces, in particular for plastic shaping of tube ends, with a shaping subassembly actuated by the pressure of a fluid—referred to there as a shaping unit—and with a clamping subassembly disposed on a common longitudinal axis and actuated by the pressure of a fluid—referred to there as a preloading unit—wherein conically configured clamping elements are provided for the workpiece. A toolset is used here for shaping and is comprised of a compression head as a compression tool and of a clamping device belong to the clamping elements. On one side the compression head contains a depression that forms a counter-contour of the to-be-formed tube contour, and on the opposite side contains an attachment means that can be attached to a corresponding connection point of a piston of the shaping subassembly, e.g., in a T-groove. The clamping device is preferably formed from a plurality of, preferably four, annularly disposed segments that function as clamping jaws. These are usually guided via cylindrical pins and held in an opening position in the unloaded state via pressure springs disposed between them. They interact with a conical surface in an opening of a yoke plate of the shaping subassembly of the device for shaping and for this purpose also have conically configured outer surfaces. During clamping the clamping jaws press onto the tube with their usually slightly roughened or toothed inside.
For the technologically important step of the tool change, it is embodied in the mentioned EP 1 494 827 B1 that a removal of device components for tool change is not required, and in a tool-change position, the tools—compression head and clamping device—can be inserted from above in corresponding openings of the shaping device, wherein a good accessibility to the tool space is provided.
In detail, with a tool change—which is not described in the document mentioned but is known from a device available on the market for deforming a tool—the process of a tool changeover can be characterized in a constructively simple embodiment by the following steps: opening a tool-change push valve of a housing of the shaping device, which housing has a basically cylindrical shape and surrounds the compression head and the clamping jaws in its work position, by pulling open by hand, inserting or changing the clamping device, inserting or changing the compression tool, e.g., by inserting into the T-groove, closing the tool-change push valve by pushing closed by hand.
Here the process represents an already optimized variant to a comparatively more complex known process of tool changeover, which is practicable, for example, with a device according to EP 1 311 358 B1 and, in particular to ensure a high assembly security, comprises the following steps: unscrewing a housing of the shaping device for the compression head and the clamping jaws, which housing has a basically truncated-cone shape, inserting or changing the clamping device, screwing-in or changing the compression tool using a special key, closing again and screwing together the housing. Here there is the risk that the clamping-jaw segments fall apart, since during the assembly they are usually held together only by a rubber ring. Furthermore the change is time consuming due to the required tool use.
It is disadvantageous in both variants that due to the space requirement necessary for the tool change the shaping region is relatively large, which leads to limitations of possible bending geometries of a to-be shaped tube, and that there is a risk of confusion of respectively mutually associated pairings of compression head and clamping device.
DE 100 40 595 A1 describes a device of the above-mentioned type and a method for shaping an end region of a workpiece, in particular for cold-press shaping of a tube end region, wherein a first hydrodynamically actuatable force transmission element for clamping the workpiece and a second hydrodynamically actuatable force-transmission element, by whose force effect the shaping is achieved, are provided. The shaping device here includes in its specific embodiment a two-part housing that is formed from a base housing and from a receptacle housing. The base housing includes a central cylindrical bore wherein an outer piston and an inner piston are guided. A compression tool is thus connectable via a rotary lock. The receptacle housing forms a receiving space for clamping jaws that are actuatable by actuating the outer piston. The assembly of the deforming tool is not described in detail, however in an analysis of the Figure drawings it appears complex in terms of assembly.
U.S. Pat. No. 5,134,872 A also describes a hydraulic clamping device for expanding a tube end. The device includes a tube-receiving end into which the to-be-expanded tube is inserted. A main piston is contained in a chuck, which main piston can be moved forward towards the tube receiving end and back again under the effect of the fluid. At one end of the main piston there is a ball for widening the tube, which ball is attached via a screw. Inside a housing are the collets, which are driven via an actuator, which in turn is screwed to a hollow actuating piston, in whose interior the main piston slides. Due to the many individual parts to be connected to one another the assembly and disassembly effort also appears disadvantageously large for this device.